Predictors of outcome in the use of cough assist machine and air stacking in neuromuscular patients

Objective: In neuromuscular diseases (NMD), the most used airway clearance techniques are mechanical in- and exsufflation (MIE) and air stacking (AS). The goal of the study was to investigate characteristics of patients treated with MIE or AS and the effect of both AS and MIE on pulmonary infections. Methods: A retrospective analysis was conducted on data related to 97 NMD patients on home mechanical ventilation using MIE (CoughAssist E70®, Philips, USA) and/or AS (Ambu balloon). We evaluated the effect of AS and MIE on pulmonary infections comparing the year before and the year after start of the therapy. Results: Patient characteristics are shown in the table. Patients that started on MIE had a lower baseline peak cough flow (PCF) compared to patients that started AS. With MIE, we were able to read out PCF from the device: PCF increased from 181 l/min (±97 l/min) to 215 l/min (±91 l/min) (p<0.05). The year before the start of therapy, 31 patients had infections—4 in the AS group and 27 in the MIE group. Instead, the year after the initiation of MIE and AS, 22 patients experienced infections: 17 in the MIE group and 5 in the AS group, respectively. There was no correlation between initial PCF values and infections after start of therapy. Conclusions: MIE was started with lower PCF. Overall, the number of infections after the use of the MIE or AS was reduced, but there was no correlation with the PCF at the start of the therapy.